Operation Popeye

Operation Popeye (Project Controlled Weather Popeye / Motorpool / Intermediary-Compatriot) was a highly classified weather modification program in Southeast Asia during 1967–1972. The cloud seeding operation during the Vietnam War ran from March 20, 1967 until July 5, 1972 in an attempt to extend the monsoon season, specifically over areas of the Ho Chi Minh Trail. The operation was used to induce rain and extend the East Asian Monsoon season in support of U.S. government efforts related to the War in Southeast Asia.

The former U.S. Secretary of Defense, Robert S. McNamara, was aware that there might be objections raised by the international scientific community but said in a memo to the president that such objections had not in the past been a basis for prevention of military activities considered to be in the interests of U.S. national security.

The chemical weather modification program was conducted from Thailand over Cambodia, Laos, and Vietnam and allegedly sponsored by Secretary of State Henry Kissinger and CIA without the authorization of then Secretary of Defense Melvin Laird who had categorically denied to Congress that a program for modification of the weather for use as a tactical weapon even existed.[1]

Build up

A report titled Rainmaking in SEASIA outlines use of lead iodide and silver iodide deployed by aircraft in a program that was developed in California at Naval Air Weapons Station China Lake and tested in Okinawa, Guam, Philippines, Texas, and Florida in a hurricane study program called Project Stormfury.[2][3]

Project Popeye was the experiment in increased rainfall through cloud seeding leading up to Operation Popeye. The technical aspects of the experiment were verified by Dr. Donald F. Hornig, Special Assistant to the President of the United States for Science and Technology. During October 1966, Project Popeye was tested in a strip of the Laos panhandle east of the Bolovens Plateau in the Se Kong River valley. The government of Laos was not informed of the project, its methods, or its goals. The test was conducted by personnel from the Naval Ordnance Test Station located at China Lake California. The results of this specific experiment are unknown, but other less surreptitious cloud seeding tests have been conducted.


Operation Popeye's goal was to increase rainfall in carefully selected areas to deny the Vietnamese enemy, namely military supply trucks, the use of roads by:[4]

  1. Softening road surfaces
  2. Causing landslides along roadways
  3. Washing out river crossings
  4. Maintaining saturated soil conditions beyond the normal time span.


The 54th Weather Reconnaissance Squadron carried out the operation using the slogan "make mud, not war."[5] Starting on March 20, 1967, and continuing through every rainy season (March to November) in Southeast Asia until 1972, operational cloud seeding missions were flown. Three C-130 Hercules aircraft and two F-4C Phantom aircraft based at Udon Thani Royal Thai Air Force Base Thailand flew two sorties per day. The aircraft were officially on weather reconnaissance missions and the aircraft crews as part of their normal duty also generated weather report data. The crews, all from the 54th Weather Reconnaissance Squadron, were rotated into the operation on a regular basis from Guam. Inside the squadron, the rainmaking operations were code-named "Motorpool".[6]

The initial area of operations was the eastern half of the Laotian panhandle. On 11 July 1967, the operational area was increased northward to around the area of the 20th parallel and included portions of far western North Vietnam. In September 1967, the A Shau Valley in South Vietnam was added to the operational area. Operations over North Vietnam were eliminated on April 1, 1968, concurrent with conventional bombing restrictions being put into effect. The southern region of North Vietnam was added to the operational area on September 25, 1968, and then removed on November 1 of that year concurrent with a halt to conventional bombing of North Vietnam. In 1972, most of northeastern Cambodia was added to the operational area.

All rainmaking operations ceased on July 5, 1972.

Public revelation

Reporter Jack Anderson published a story in March 1971 concerning Operation Popeye (though in his column, it was called Intermediary-Compatriot). The name Operation Popeye (Pop Eye) entered the public space through a brief mention in the Pentagon Papers[7] and a July 3, 1972, article in the New York Times.[8] Operations in Laos ceased two days after the publication of the Times article.

The press stories led to demands from members of the U.S. Congress, led by Senator Claiborne Pell, for more information. U.S. House and Senate resolutions in favor of banning environmental warfare were passed as Senate Resolution 71 on July 11, 1973, H.R. 116 of 1974, H.R. 329 of 1974 and H.R. 28 of 1975.

Current legal status

Weather modification procedures, when performed to achieve a military end, now fall under the provenance of the Environmental Modification Convention.

See also


  • Weather Modification Hearing, United States Senate Subcommittee on Oceans and International Environment of the Committee on Foreign Relations, March 20, 1974

Published government documents

  • Keefer, Edward C. Foreign Relations of the United States 1964-1968 Volume XXVII Laos United States Government Printing Office, 1998.


  1. ^ "Rainmaking used as a Weapon in SE Asia". Daytona Beach Morning Journal. Daytona Beach, Florida. New York Times News Service. May 19, 1974.
  2. ^ SEASIA Rainmaking (Report). Department of Defense. 1974. Archived from the original on 2009-06-12.
  3. ^ Project Stormfury (PDF) (Report). Department of the Navy. May 1971.
  4. ^ "ENMOD and the US Congress". Sunshine-project.org. Archived from the original on 2009-08-27. Retrieved 2009-07-25.
  5. ^ Will Thomas Author. "Weather Warfare/Global Dominance Over Weather/Full Spectrum Dominance By Us Over Weather". Willthomas.net. Archived from the original on 2007-02-23. Retrieved 2009-07-25.
  7. ^ "The Pentagon Papers, Gravel Edition, Volume 4, Chapter 2, "US Ground Strategy and Force Deployments, 1965-1968, pp. 277-604, 3rd section". Mtholyoke.edu. Retrieved 2009-07-25.
  8. ^ Seymour M. Hersh (July 3, 1972). "Rainmaking Is Used As Weapon by U.S.; Cloud-Seeding in Indochina Is Said to Be Aimed at Hindering Troop Movements and Suppressing Antiaircraft Fire Rainmaking Used for Military Purposes by the U.S. in Indochina Since '63". New York Times. Retrieved 2009-07-25.

External links

54th Weather Reconnaissance Squadron

The 54th Weather Reconnaissance Squadron is an inactive United States Air Force unit. Its last assignment was to the 41st Rescue and Weather Reconnaissance Wing at Andersen Air Force Base, Guam, where it was inactivated on 30 September 1987.

Brazilian Armed Forces

The Brazilian Armed Forces (Portuguese: Forças Armadas Brasileiras, IPA: [ˈfoʁsɐz ɐʁˈmadɐz bɾaziˈlejɾɐs]) is the unified military organization comprising the Brazilian Army (including the Brazilian Army Aviation), the Brazilian Navy (including the Brazilian Marine Corps and Brazilian Naval Aviation) and the Brazilian Air Force.Brazil's armed forces are the third largest in the Americas, after the United States and Colombia, and the largest in Latin America by the level of military equipment, with 318,480 active-duty troops and officers. With no serious external or internal threats, the armed forces are searching for a new role. They are expanding their presence in the Amazon under the Northern Corridor (Calha Norte) program. In 1994 Brazilian troops joined United Nations (UN) peacekeeping forces in five countries. Brazilian soldiers have been in Haiti since 2004 leading the United Nations Stabilization Mission (MINUSTAH).The Brazilian military, especially the army, has become more involved in civic-action programs, education, health care, and constructing roads, bridges, and railroads across the nation. Although the 1988 constitution preserves the external and internal roles of the armed forces, it places the military under presidential authority. Thus, the new charter changed the manner in which the military could exercise its moderating power.

Cloud seeding

Cloud seeding is a type of weather modification that aims to change the amount or type of precipitation that falls from clouds by dispersing substances into the air that serve as cloud condensation or ice nuclei, which alter the microphysical processes within the cloud. The usual intent is to increase precipitation (rain or snow), but hail and fog suppression are also widely practised in airports where harsh weather conditions are experienced.

Cloud seeding also occurs due to ice nucleators in nature, most of which are bacterial in origin.

Environmental Modification Convention

The Environmental Modification Convention (ENMOD), formally the Convention on the Prohibition of Military or Any Other Hostile Use of Environmental Modification Techniques is an international treaty prohibiting the military or other hostile use of environmental modification techniques having widespread, long-lasting or severe effects. It opened for signature on 18 May 1977 in Geneva and entered into force on 5 October 1978.

The Convention bans weather warfare, which is the use of weather modification techniques for the purposes of inducing damage or destruction. The Convention on Biological Diversity of 2010 would also ban some forms of weather modification or geoengineering.Many states do not regard this as a complete ban on the use of herbicides in warfare, such as Agent Orange, but it does require case-by-case consideration.

Hands-On Mobile

Hands-On Mobile is a wireless entertainment company, established in 2001.

The company develops, publishes and distributes mobile content via network operators and portals. It offers its content in or via Java ME, BREW, SMS, MMS, and WAP in English, French, Italian, Spanish, German, Portuguese, Czech, Chinese and Korean.

Hands-On Mobile is a private company headquartered in San Francisco, California. It has further offices in San Diego, London and Manchester (UK), Madrid (Spain), Paris (France), Munich (Germany), Beijing and Shanghai (China), and São Paulo (Brazil).

Hands-On Mobile's investors include eFund, Draper Fisher Jurvetson, General Catalyst Partners, Institutional Venture Partners and Bessemer Venture Partners.

Joint Security Area

The Joint Security Area (JSA) is the only portion of the Korean Demilitarized Zone (DMZ) where North and South Korean forces stand face-to-face. It is often called the Truce Village of Panmunjom (the Truce Village; or simply, Panmunjom) in the media and various military accounts.The JSA is used by the two Koreas for diplomatic engagements and, until March 1991, was also the site of military negotiations between North Korea and the United Nations Command (UNC). In 2018, North and South Korean officials ordered the JSA to be cleared of all landmines, weapons, guard posts, and personnel. This withdrawal was complete on October 25, 2018 and the JSA now just contains 35 unarmed security guards. The area will also no longer function in its current state and it was agreed that it will now just serve as a tourist attraction. On November 6, 2018, it was announced that the UNC would transfer primary guard duties of the now demilitarized Joint Security Area to both North and South Korea.

List of allied military operations of the Vietnam War (1967)

This article is a list of known military operations of the Vietnam War in 1967, conducted by the armed forces of the Republic of Vietnam, the United States and their allies.

List of allied military operations of the Vietnam War (M–S)

This article is a list of known military operations of the Vietnam War, a war fought by the United States to try to stop communism in Southeast Asia, conducted by the armed forces of the Republic of Vietnam, the United States and allies consisting of Australia, New Zealand, Thailand, South Korea, and the Philippines. This is not a complete list. Operations are currently listed alphabetically, but are being progressively reorganised as a chronology.

Lockheed WC-130

The Lockheed WC-130 is a high-wing, medium-range aircraft used for weather reconnaissance missions by the United States Air Force. The aircraft is a modified version of the C-130 Hercules transport configured with specialized weather instrumentation including a dropsonde deployment/receiver system and crewed by a meteorologist for penetration of tropical cyclones and winter storms to obtain data on movement, size and intensity.

The Air Weather Service (AWS) received its first C-130 Hercules in 1962 to conduct air sampling missions in the wake of a resumption of atmospheric weapons testing by the Soviet Union in September 1961. The Air Force was then in the process of replacing its fleet of WB-50 weather reconnaissance aircraft with WB-47E jets but by 1965 the AWS had decided it would better served by the WC-130 in the manned weather reconnaissance role. Since that year the Air Force and Air Force Reserve have operated a total of 50 WC-130s in five variants. The WC-130J Weatherbird is the current weather data collection platform for the 53rd Weather Reconnaissance Squadron.

Only one WC-130 has been lost during operational missions, H-model 65-0965, on 12 October 1974, flying Typhoon Bess northeast of The Philippines. A former weather recon aircraft, H-model 65-0968, was lost on 2 May 2018 while serving with the Puerto Rico Air National Guard on its final ferry flight to retirement. Two WC-130B models were lost to crashes after being sold to international customers, and another operational WC-130B aircraft was destroyed on the ground by a hurricane.


Motorpool may refer to

Various automotive-related topics

Fleet vehicle, an internally shared resource owned or leased by a business, government agency or other entity

Carsharing, involving a group of vehicles whose usage is shared among the general public or a membership group

Carpool, the sharing of car journeys so that more than one person travels in each car

Motorpool.com, a social media web site for classic car enthusiasts created by Morgan Murphy (food critic)

Other topics

Motor pool (neuroscience), the group of motor neurons that innervate a muscle

Operation Popeye, a highly classified weather modification program in Southeast Asia during 1967–1972

Olímpio Mourão Filho

Olímpio Mourão Filho (9 March 1900 – 28 May 1972) was a Brazilian general who actively participated in the integralist movement and in the coup d'état of 1964. He was the editor of the Cohen plan, a document falsely attributed to international communism, which was used as justification for the instatement of the Estado Novo regime of Getúlio Vargas.

On 31 March 1964 he ordered the troops of the 4th infantry division under his command in Juiz de Fora to march on the city of Rio de Janeiro, an action that precipitated the military coup a few days before the date planned by the conspirators. Between 1967 and 1969 he was president of the Supreme Military Tribunal.

Operation Commando Hunt

Operation Commando Hunt was a covert U.S. Seventh Air Force and U.S. Navy Task Force 77 aerial interdiction campaign that took place during the Vietnam War. The operation began on 11 November 1968 and ended on 29 March 1972. The objective of the campaign was to prevent the transit of People's Army of Vietnam (PAVN) personnel and supplies on the logistical corridor known as the Ho Chi Minh Trail (the Truong Son Road to the North Vietnamese) that ran from the southwestern Democratic Republic of Vietnam (North Vietnam) through the southeastern portion of the Kingdom of Laos and into the Republic of Vietnam (South Vietnam).

Outline of the Vietnam War

The following outline is provided as an overview of and topical guide to the Vietnam War:

Vietnam War – Cold War-era proxy war that occurred in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. This war followed the First Indochina War (1946–54) and was fought between North Vietnam—supported by the Soviet Union, China and other communist allies—and the government of South Vietnam—supported by the United States, Philippines and other anti-communist allies. The Viet Cong (also known as the National Liberation Front, or NLF), a South Vietnamese communist common front aided by the North, fought a guerrilla war against anti-communist forces in the region. The People's Army of Vietnam, also known as the North Vietnamese Army (NVA), engaged in a more conventional war, at times committing large units to battle.

Project Stormfury

Project Stormfury was an attempt to weaken tropical cyclones by flying aircraft into them and seeding with silver iodide. The project was run by the United States Government from 1962 to 1983.

The hypothesis was that the silver iodide would cause supercooled water in the storm to freeze, disrupting the inner structure of the hurricane. This led to the seeding of several Atlantic hurricanes. However, it was later shown that this hypothesis was incorrect. It was determined that most hurricanes do not contain enough supercooled water for cloud seeding to be effective. Additionally, researchers found that unseeded hurricanes often undergo the same structural changes that were expected from seeded hurricanes. This finding called Stormfury's successes into question, as the changes reported now had a natural explanation.

The last experimental flight was flown in 1971, due to a lack of candidate storms and a changeover in NOAA's fleet. More than a decade after the last modification experiment, Project Stormfury was officially canceled. Although a failure in its goal of reducing the destructiveness of hurricanes, Project Stormfury was not without merit. The observational data and storm lifecycle research generated by Stormfury helped improve meteorologists' ability to forecast the movement and intensity of future hurricanes.


Rainmaking, also known as artificial precipitation, artificial rainfall and pluviculture, is the act of attempting to artificially induce or increase precipitation, usually to stave off drought or the wider global warming. According to the clouds' different physical properties, this can be done using airplanes or rockets to sow to the clouds with catalysts such as dry ice, silver iodide and salt powder, to make clouds rain or increase precipitation, to remove or mitigate farmland drought, to increase reservoir irrigation water or water supply capacity, to increase water levels for power generation, or even to solve the global warming problem.

In the United States, rainmaking was attempted by traveling showmen. It was practiced in the old west, but may have reached a peak during the dust bowl drought of the American West and Midwest in the 1930s. The practice was depicted in the 1956 film The Rainmaker. Attempts to bring rain directly have waned with development of the science of meteorology, the advent of laws against fraud and increased communication technology, with some exceptions such as cloud seeding and forms of prayer including rain dances, which are still practiced today. Prayer for more rain is also a cultural practice for Christians and Muslims in areas which people keep "traditional" non-scriptural religions. In the Christian areas the Defteras (learned clerics of the Orthodox Christian Church) believed to have the wisdom to arrest the rain, to bring hail to farms of individuals who refuse to comply with religious rules as well as to bring more rains when the rainy season fell short of giving the usual amount of rain needed for growing cereals.The term is also used metaphorically to describe the process of bringing new clients into a professional practice, such as law, architecture, consulting, advertising, or investment banking—in general, processes that bring money into a company.

It is also used to describe a confidence trick where the scammer takes money from the victim to influence a system over which they have no real control, but a random chance of the outcome happening anyway.


Weather is the state of the atmosphere, describing for example the degree to which it is hot or cold, wet or dry, calm or stormy, clear or cloudy. Most weather phenomena occur in the lowest level of the atmosphere, the troposphere, just below the stratosphere. Weather refers to day-to-day temperature and precipitation activity, whereas climate is the term for the averaging of atmospheric conditions over longer periods of time. When used without qualification, "weather" is generally understood to mean the weather of Earth.

Weather is driven by air pressure, temperature and moisture differences between one place and another. These differences can occur due to the sun's angle at any particular spot, which varies with latitude. The strong temperature contrast between polar and tropical air gives rise to the largest scale atmospheric circulations: the Hadley Cell, the Ferrel Cell, the Polar Cell, and the jet stream. Weather systems in the mid-latitudes, such as extratropical cyclones, are caused by instabilities of the jet stream flow. Because the Earth's axis is tilted relative to its orbital plane, sunlight is incident at different angles at different times of the year. On Earth's surface, temperatures usually range ±40 °C (−40 °F to 100 °F) annually. Over thousands of years, changes in Earth's orbit can affect the amount and distribution of solar energy received by the Earth, thus influencing long-term climate and global climate change.

Surface temperature differences in turn cause pressure differences. Higher altitudes are cooler than lower altitudes, as most atmospheric heating is due to contact with the Earth's surface while radiative losses to space are mostly constant. Weather forecasting is the application of science and technology to predict the state of the atmosphere for a future time and a given location. The Earth's weather system is a chaotic system; as a result, small changes to one part of the system can grow to have large effects on the system as a whole. Human attempts to control the weather have occurred throughout history, and there is evidence that human activities such as agriculture and industry have modified weather patterns.

Studying how the weather works on other planets has been helpful in understanding how weather works on Earth. A famous landmark in the Solar System, Jupiter's Great Red Spot, is an anticyclonic storm known to have existed for at least 300 years. However, weather is not limited to planetary bodies. A star's corona is constantly being lost to space, creating what is essentially a very thin atmosphere throughout the Solar System. The movement of mass ejected from the Sun is known as the solar wind.

Weather modification

Weather modification is the act of intentionally manipulating or altering the weather. The most common form of weather modification is cloud seeding, which increases rain or snow, usually for the purpose of increasing the local water supply. Weather modification can also have the goal of preventing damaging weather, such as hail or hurricanes, from occurring; or of provoking damaging weather against the enemy, as a tactic of military or economic warfare like Operation Popeye, where clouds were seeded to prolong the monsoon in Vietnam. Weather modification in warfare has been banned by the United Nations under Environmental Modification Convention.

Weather warfare

Weather warfare is the use of weather modification techniques such as cloud seeding for military purposes.

Prior to the Environmental Modification Convention signed in Geneva in 1977, the United States used weather warfare in the Vietnam War. Under the auspices of the Air Weather Service, the United States' Operation Popeye used cloud seeding over the Ho Chi Minh trail, increasing rainfall by an estimated thirty percent during 1967 and 1968. It was hoped that the increased rainfall would reduce the rate of infiltration down the trail.With much less success, the United States also dropped salt on the airbase during the siege of Khe Sanh in an attempt to reduce the fog that hindered air operations.A research paper produced for the United States Air Force written in 1996 speculates about the future use of nanotechnology to produce "artificial weather", clouds of microscopic computer particles all communicating with each other to form an intelligent fog that could be used for various purposes. "Artificial weather technologies do not currently exist. But as they are developed, the importance of their potential applications rises rapidly." Weather modification technologies are described in an unclassified academic paper written by air force officer-cadet students as "a force multiplier with tremendous power that could be exploited across the full spectrum of war-fighting environments."The Convention on the Prohibition of Military or Any Other Hostile Use of Environmental Modification Techniques (Geneva: May 18, 1977, Entered into force: October 5, 1978) prohibits "widespread, long-lasting or severe effects as the means of destruction, damage or injury". However, it has been argued that this permits "local, non-permanent changes". In contrast, the "Consultative Committee of Experts" established in Article VIII of the Convention has stated in their "Understanding relating to Article II" that any use of environmental modification where this is done "as a means of destruction, damage or injury to another State Party, would be prohibited.". Furthermore, they conclude in the same paragraph that "military or any other hostile use of environmental modification techniques, would result, or could reasonably be expected to result, in widespread, long-lasting or severe destruction, damage or injury.", meaning that all signatories are expected to abstain from using weather modification to cause harm at any scale. Importantly, the language of the treaty does not overtly condemn military use of weather modification when it does not directly cause harm, such as the United States' use of weather modification in the siege of Khe Sanh, discussed above. Because of the limitations of the treaty, and the fact that it applies only to signatory states, weather warfare is not a thing of the past, and may continue to play a role in warfare throughout the twenty-first century.

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